A series of free base and zinc porphyrins, mono meso-substituted with a pyridyl group via an amide link, have been prepared by stepwise functionalisation of free base tetraphenylporphyrin, H2tpp. Four [W(CO)5L] (L = pyridyl-porphyrin) complexes have been synthesised; [Mtpp-NHCO-py-W(CO)5}], where M = 2H or Zn, one phenyl group is substituted at the 4-position and the pyridine is substituted at the 3- or 4-position. The spectroscopic data of the [W(CO)5L] complexes have been compared with those of the porphyrin ligands alone and with those of the model compounds, [W(CO)5(3-H2NCO-py)] and [W(CO)5(4-H2NCO-py)]. The UV-Vis spectra of the model compounds show that the MLCT and LF absorption bands overlap and no emission is observed at room temperature in solution. The UV-Vis absorption and emission spectra of the porphyrins with peripheral W(CO)5 are dominated by porphyrin bands. Time-resolved emission was observed from the porphyrin moiety in the [W(CO)5L] complexes and fitted to mono-exponential kinetics to give lifetimes of ≤10 ns for the zinc porphyrins and of ca. 22 ns for the free base porphyrins. Transients characteristic of the porphyrin 3(π–π*) excited state have been observed by time-resolved absorption and their decay kinetics have been fitted to an appropriate rate law. Long wavelength photolysis of [W(CO)5(3-H2NCO-py)] and [W(CO)5(4-H2NCO-py)] in THF resulted in conversion to [W(CO)5(THF)]. The [W(CO)5L] complexes behaved similarly with photolysis at λ > 395 nm but were photostable with λ > 495 nm.
通过逐步官能化游离碱
四苯基卟啉 H2tpp 制备了一系列通过酰胺键被
吡啶基单内消旋取代的游离碱和
锌卟啉。合成了四种[W(CO)5L](L=
吡啶基
卟啉)配合物; [Mtpp-NHCO-py-W(CO)5}],其中M=2H或Zn,一个苯基在4-位被取代并且
吡啶在3-或4-位被取代。 [W(CO)5L]配合物的光谱数据与单独的
卟啉配体以及模型化合物[W(CO)5(3-H2NCO-py)]和[W(CO)的光谱数据进行了比较)5(4-H2NCO-py)]。模型化合物的紫外-可见光谱表明,MLCT 和 LF 吸收带重叠,并且在室温溶液中没有观察到发射。具有外围 W(CO)5 的
卟啉的紫外-可见吸收和发射光谱以
卟啉谱带为主。从 [W(CO)5L] 配合物中的
卟啉部分观察到时间分辨发射,并拟合单指数动力学,得出
锌卟啉的寿命≤10 ns,寿命约为 10 ns。游离碱
卟啉为 22 ns。
卟啉 3(π–π*) 激发态的瞬态特征已通过时间分辨吸收观察到,并且其衰变动力学已符合适当的速率定律。 [W(CO)5(3-H2NCO-py)] 和 [W(CO)5(4-H2NCO-py)] 在 THF 中的长波长光解导致转化为 [W(CO)5(THF)]。 [W(CO)5L] 配合物在 λ > 395 nm 处的光解作用相似,但在 λ > 495 nm 处具有光稳定性。